1. Open your Outlook 2013 Client.
2. From within the Ribbon, locate the Find grouping, click the Address Book Button.
3. When the Address List window appears, click Tools then Options.
4. The Addressing settings are defaulted to the Global Address List. To choose a different primary list, when sending an e-mail message, select the radial button that fits the Address Book type or add a custom one. To change the default Address Book when opening the Address Book directly, select the desired Address Book from the drop down menu labeled "When opening the address book, show this address first:"
5. Click OK to save your changes.